metamorphic

Polished tiger’s-eye

Quartz-rich aggregate with chatoyant fibrous crocidolite pseudomorphs; mainly SiO₂

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; golden-brown to dark brown silky bands, vitreous-to-waxy luster, and no obvious cleavage. Its chatoyancy (cat’s-eye shimmer) results from aligned fibers; specific gravity is roughly 2.6–2.7.

Identified September 10, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz replaces crocidolite (blue asbestos) fibers during low-grade alteration, preserving the fibrous texture; commonly associated with Precambrian rocks. The specimen is tumbled and polished.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and lapidary collectibles; rarely used industrially beyond quartz aggregate.

Geological facts

Tiger’s-eye is a pseudomorph: quartz takes the place of another mineral while retaining its structure. Golden varieties are common; blue hawk’s-eye represents less-altered material.

Field identification & locations

Identify by its parallel silky bands and moving, reflective cat’s-eye line under directional light; it is notably denser and harder than dyed glass or plastic. Major sources include South Africa, Western Australia, India, Brazil, and Namibia.